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Alex Cohen Proves Fractal Uncertainty Principle at 25

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Alex Cohen, a 25-year-old doctoral student at MIT, extended the fractal uncertainty principle to higher dimensions in 2025. Building on work by Semyon Dyatlov and Jean Bourgain, Cohen proved that quantum particles cannot follow fractal paths due to inherent wave-like behavior. This breakthrough, published in the *Annals of Mathematics*, redefines how quantum systems differ from classical chaos. The principle links quantum uncertainty to fractal geometry, showing that fractal-like functions and their Fourier transforms cannot coexist. Cohen’s work earned him an assistant professorship at NYU, cementing his role in advancing quantum mathematics.

Dyatlov initially proposed the principle for one-dimensional fractals, inspired by chaotic systems like billiard ball paths. His 2016 research, aided by Bourgain, aimed to generalize it but faced skepticism. Cohen’s success came after years of refining harmonic analysis techniques. His proof revealed that quantum particles, described by wavefunctions, inherently resist fractal confinement—unlike classical objects that might trap in fractal dust. This distinction highlights a foundational difference between quantum and classical physics.

The fractal uncertainty principle stems from Fourier transforms, which decompose functions into frequencies. A fractal’s porous structure (like the Cantor set) cannot translate to a fractal frequency set. This mathematical constraint explains why quantum waves leak from fractal traps. Researchers like Peter Sarnak called it a "foundational result," noting its implications for chaotic systems. The principle also connects to real-world applications, such as signal processing, where uncertainty between time and frequency domains mirrors quantum behavior.